The present invention relates to a liquid crystal display device and, more specifically, to a technology that works well with a liquid crystal display device in which a substrate sandwiching a liquid crystal material with another substrate carries thereon a common electrode and a pixel electrode, and the pixel electrode is disposed above the common electrode via an insulator layer, and includes a comb-like electrode section.
The liquid crystal display device falls into two broad categories of VA (Vertical Alignment) and IPS (In-plane Switching) in view of the direction of an electric field for application to a liquid crystal material, i.e., liquid crystal layer.
In a VA-mode liquid crystal display device, on a substrate sandwiching a liquid crystal material with another substrate, a pixel electrode is disposed, and on the other substrate, a common electrode is so disposed as to oppose the pixel electrode. The common electrode is referred to also as opposing electrode. The VA-mode liquid crystal display is typified also by a TN (Twisted Nematic) mode.
In an IPS-mode liquid crystal display device, on the other hand, on a substrate sandwiching a liquid crystal material with another substrate, a pixel electrode and a common electrode are both disposed. Compared with the VA-mode liquid crystal display device, the IPS-mode liquid crystal display device can easily have a wider viewing angle, and thus has become popular for use in liquid crystal televisions.
In the IPS-mode liquid crystal display device, one substrate carries thereon both a pixel electrode and a common electrode. For the IPS-mode liquid crystal display device, there thus has been proposed various electrode layouts and shapes to achieve efficient application of an electric field to a liquid crystal layer. The electric field is the one to be generated by a potential difference between the pixel and common electrodes.
As one possible layout of the pixel and common electrodes in the IPS-mode liquid crystal display device, the pixel electrode is disposed on the common electrode with an insulator layer therebetween. With such a layout, for example, the common electrode is shaped flat, and the pixel electrode is shaped like a comb. As an example, refer to Patent Document 1 (U.S. Pat. No. 6,233,034).
In an exemplary liquid crystal display device in which a substrate carries thereon a flat-shaped common electrode with a comb-like pixel electrode thereabove with an insulator layer disposed therebetween, a liquid crystal layer is made of a material with a positive dielectric anisotropy, for example.